The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
A wireless network generally refers to a network of devices that are linked together through a wireless medium, and communicate over the wireless medium via a wireless distribution method—e.g., spread-spectrum or orthogonal frequency-division multiplexing (OFDM). A wireless network typically operates in accordance with processes specified in one or more standards of wireless communication (also referred to herein as “wireless communication standards”). Different methods and standards of wireless communication can generally be classified into the four following categories, identified in the headings below, based on a specific application and/or transmission range.
Personal Area Network (PAN)
A Personal Area Network (PAN) is a computer network used for short range communication among devices (including telephones and personal digital assistants). The reach of a PAN is typically a few meters. PAN's can be used for communication among a particular group of devices themselves (intrapersonal communication), or for connecting to a higher level network and/or the Internet. Personal area networks may be wired with computer buses such as USB and FireWire. However, a wireless Personal Area Network (WPAN) is typically made possible with wireless communication standards such as Infrared and Bluetooth™.
In particular, the Infrared Data Association (IrDA) defines physical specifications communications protocol standards for the short range exchange of data over infrared light, for typical use in Personal Area Networks. Bluetooth is an industrial specification for wireless personal area networks (PANS), also known as IEEE 802.15.1. Bluetooth provides a way to connect and exchange information between devices such as personal digital assistants (PDAs), mobile phones, laptops, PCs, printers, digital cameras and video game consoles via a secure, globally unlicensed short-range radio frequency.
Local Area Network (LAN)
A wireless Local Area Network (wireless LAN or WLAN) generally corresponds to the linking of two or more devices without using wires. A WLAN utilizes spread-spectrum or OFDM technology based on radio waves to enable communication between devices in a limited area, also known as the basic service set (BSS). The IEEE 802.11 standard, also commonly referred to as the Wi-Fi standard, denotes a set of Wireless LAN/WLAN standards developed by working group 11 of the IEEE LAN/MAN Standards Committee (IEEE 802). The IEEE 802.11 standard supports two types (or modes) of wireless LAN networks—i) infrastructure mode or ESS networks, and ii) ad-hoc mode or IBSS (independent BSS) network.
Metropolitan Area Network (MAN)
Wireless Metropolitan Area Network (MAN) is the name trademarked by the IEEE 802.16 Working Group on Broadband Wireless Access Standards for its wireless metropolitan area network standard (commercially known as WiMAX), which defines broadband Internet access from fixed or mobile devices via antennas. WiMAX is defined as Worldwide Interoperability for Microwave Access by the WiMAX Forum, formed in June 2001 to promote conformance and interoperability of the IEEE 802.16 standard, officially known as WirelessMAN. In accordance with the WiMAX standard, subscriber stations can communicate with base-stations that are connected to a core network.
Wide Area Network (WAN)
A Wide Area Network or WAN is a computer network covering a broad geographical area—in contrast to personal area networks (PANS), local area networks (LANs) or metropolitan area networks (MANS) which are typically limited to a room, building or campus. The largest and most well-known example of a WAN is the Internet. In addition, WANs also refer to Mobile Data Communications, such as GSM (Global System for Mobile Communications), GPRS (General Packet Radio Service), EDGE (Exchanged Data rates for GSM Evolution), 3G, HSDPA (High speed Downlink Packet Access), and the like.
A wireless communication standard typically specifies one or more protocols or processes that enable a wireless device to discover another wireless device. Such protocols are commonly referred to as discovery protocols. For example, in accordance with a discovery protocol associated with an infrastructure mode wireless LAN (or ESS network), an access point (AP) advertises its presence by transmitting short wireless messages (referred to as beacons) at a regular interval (e.g., approximately every 100 mSec) on one of a number of radio frequencies (or channels) that may be available for communication. The beacons include information about the capabilities of the access point and also serve as a timing reference for some of the protocol operations such as power saving modes. The capabilities advertised in a beacon include information corresponding to the network name or SSID, the supported data rates, and so on. Wireless devices can connect with an AP in an ESS network either through performing an active scanning process or a passive scanning process. An active scanning process involves a wireless device sending a probe request to the AP (and then eventually receiving a probe response); while in a passive scanning process, a wireless device listens for beacons on one of a number of radio frequencies (or channels) that may be available for communication. Once a wireless device discovers the identity of an AP, the wireless device can then proceed with authentication procedures as specified, e.g., in IEEE 801.11 standard (which is incorporated herein by reference).
In accordance with a discovery protocol associated with an IBSS network, a first device can discover one or more second devices by first initially listening for a beacon from a second device. In response to the first device not receiving any beacons, the first device typically waits for a random time (within a fixed range) prior to sending beacons. However, in response to the first device receiving a beacon from a second device, the first device can then synchronize its timing with the second device, and the two devices may share the process of sending beacons according to an algorithm as defined in the IEEE 802.11 standard.
In an area or location in which there may be a large number (e.g., 10 or more) of wireless devices and/or users of wireless devices (e.g., an entertainment venue such as a sports stadium or a concert) a substantial portion of the communication over various wireless channels can comprise discovery-related traffic—e.g., beacons, probe requests, probe responses, and the like—which can reduce an overall bandwidth of the wireless channels in terms of data communications. Such a loss in overall bandwidth can be attributed in part to conventional discovery protocols generally specifying processes (or steps) to be performed by a wireless device (to discover another wireless device) irrespective of a number of wireless devices that may be present within a given area or location.